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statx.2: ffix 

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This commit is contained in:
Michael Kerrisk 2020-11-01 07:15:54 +01:00
parent e9c09849cc
commit 2e33563284
1 changed files with 5 additions and 5 deletions
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10
man2/statx.2
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@ -463,26 +463,26 @@ It cannot be written to, and all reads from it will be verified
against a cryptographic hash that covers the against a cryptographic hash that covers the
entire file (e.g., via a Merkle tree). entire file (e.g., via a Merkle tree).
.TP .TP
.BR STATX_ATTR_DAX (since Linux 5.8) .BR STATX_ATTR_DAX " (since Linux 5.8)"
The file is in the DAX (cpu direct access) state. The file is in the DAX (cpu direct access) state.
DAX state attempts to DAX state attempts to
minimize software cache effects for both I/O and memory mappings of this file. minimize software cache effects for both I/O and memory mappings of this file.
It requires a file system which has been configured to support DAX. It requires a file system which has been configured to support DAX.
.PP .IP
DAX generally assumes all accesses are via CPU load / store instructions DAX generally assumes all accesses are via CPU load / store instructions
which can minimize overhead for small accesses, which can minimize overhead for small accesses,
but may adversely affect CPU utilization for large transfers. but may adversely affect CPU utilization for large transfers.
.PP .IP
File I/O is done directly to/from user-space buffers and memory mapped I/O may File I/O is done directly to/from user-space buffers and memory mapped I/O may
be performed with direct memory mappings that bypass the kernel page cache. be performed with direct memory mappings that bypass the kernel page cache.
.PP .IP
While the DAX property tends to result in data being transferred synchronously, While the DAX property tends to result in data being transferred synchronously,
it does not give the same guarantees as the it does not give the same guarantees as the
.B O_SYNC .B O_SYNC
flag (see flag (see
.BR open (2)), .BR open (2)),
where data and the necessary metadata are transferred together. where data and the necessary metadata are transferred together.
.PP .IP
A DAX file may support being mapped with the A DAX file may support being mapped with the
.B MAP_SYNC .B MAP_SYNC
flag, which enables a flag, which enables a